Question

If cos(-ϴ)=0.95, find sin(π/2-ϴ)

Answer 1

$\bf \textit{Cofunction Identities} \\\\ sin\left(\frac{\pi}{2}-\theta\right)=cos(\theta) \qquad cos\left(\frac{\pi}{2}-\theta\right)=sin(\theta) \\\\\\ \stackrel{\textit{symmetry identities}}{cos(-\theta )=cos(\theta )}\\\\ -------------------------------\\\\ sin\left(\frac{\pi}{2}-\theta\right)=cos(\theta)=cos(-\theta )=0.95$